DEV Community

Ashish Prajapati
Ashish Prajapati

Posted on

Intro to bash

#bash #cli

Bash is a shell, or commend language interpreter, for the GNU operating system

Example. $USER and $PWD are variables

  • echo “print” # to print something 
val=1
val=$((val+1)) # it increases the value by 1
Enter fullscreen mode Exit fullscreen mode
  • We can use let val+=1 to increase its value 
fix=2
for ((i = 1; i <= 99; i++)) 
do
    if [ $((i%fix)) -eq 1 ] 
    then
        echo "Number: $i"
    fi
done

output: 1, 3, 5, 7, 9, 11, ....., 99
Enter fullscreen mode Exit fullscreen mode
  • read is used to take input
  • Comparing numbers: 
  read X
  read Y

  if [ $X -lt $Y ] ; 
  then
      echo "X is less than Y"
  elif [ $X -gt $Y ] ;
  then
      echo "X is greater than Y"
  else
      echo "X is equal to Y"
      fi
Enter fullscreen mode Exit fullscreen mode
  • Comparing multiple conditions: 
read c
if [[ c=="Y" || c=="y" ]]
then
    echo "YES"
else 
    echo "NO"
    fi
Enter fullscreen mode Exit fullscreen mode

Top comments (0)

Read next

siddhantkcode profile image

Building smarter Docker Images for your development environments with Pants 🚀

Siddhant Khare -

yrizos profile image

Setting Up Visual Studio Code for Rust on macOS

Yannis Rizos -

raielly profile image

How to Fix "MySQL Shutdown Unexpectedly"

raielly -

tomj profile image

Web Images: Resize and Convert Perfectly (and Automatically)

Tom J. -